Acquisitions - Additional Information (Details)		1 Months Ended			12 Months Ended
	Apr. 01, 2017 USD ($) shares	Apr. 30, 2015 USD ($) Installment shares	Mar. 31, 2014 USD ($) Project	Feb. 28, 2014 USD ($) shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Apr. 30, 2016 USD ($) shares	Oct. 31, 2015 USD ($) shares
Business Acquisition [Line Items]
Power purchase or lease agreement term					20 years
Goodwill					$ 87,543,000	$ 51,786,000
Scenario Forecast
Business Acquisition [Line Items]
Business acquisition contingent cash payment	$ 9,100,000
Business acquisition contingent share issuance | shares	600,000
Business acquisition of compensation expenses	2 years
Mainstream Energy Corporation
Business Acquisition [Line Items]
Purchase consideration for assets acquired and liabilities assumed				$ 78,800,000	78,750,000
Cash payment				1,800,000
Purchase consideration amount of settlement on pre existing relationship				1,800,000
Business acquisition acquired business to total revenue						$ 114,200,000
Goodwill					51,786,000
Mainstream Energy Corporation | Stock Options
Business Acquisition [Line Items]
Purchase consideration amount on issuance of shares				$ 200,000
Business acquisition, shares issued | shares				576,878
Mainstream Energy Corporation | Common Stock
Business Acquisition [Line Items]
Purchase consideration amount on issuance of shares				$ 75,000,000
Business acquisition, shares issued | shares				12,762,894
Clean Energy Experts, LLC
Business Acquisition [Line Items]
Purchase consideration for assets acquired and liabilities assumed					43,717,000
Purchase consideration amount on issuance of shares		$ 19,100,000
Business acquisition, shares issued | shares		1,400,000
Cash payment		$ 25,000,000
Business acquisition acquired business to total revenue					16,900,000
Business acquisition shares of common stock | shares		1,900,000
Business acquisition payment of cash		$ 15,000,000
Remaining cash of business acquisition		$ 10,000,000
Remaining shares of business acquisition | shares		500,000
Number of installment | Installment		2
Business acquisition cash to be paid in October 2015 and in April 2016								$ 5,000,000
Business acquisition shares to be issued in October 2015 and in April 2016 | shares								250,000
Goodwill					$ 35,757,000
Clean Energy Experts, LLC | Scenario Forecast
Business Acquisition [Line Items]
Business acquisition cash to be paid in October 2015 and in April 2016							$ 5,000,000
Business acquisition shares to be issued in October 2015 and in April 2016 | shares							250,000
Solar Projects
Business Acquisition [Line Items]
Payments to acquire solar projects and the associated leases			$ 39,400,000
Number of projects | Project			2,924
Power purchase or lease agreement term			20 years
Lease premiums or discounts			$ 0
Goodwill			$ 0